Regulating centkieugal pumps



A. F. SHERZER REGULATING CENTRIFUGAL PUMPS Filed July 23. 1,921

My): area".

Patented Aug. 14, 1923.

UNITED STATES ALLEN F. SHERZER, OF YPSILANTI, MICHIGAN.

REGULA'IING CENTRIFU GAL PUMPS.

Application filed July 23, 1921.

To all whom it may concern.

Be it known that I, ALLEN F. SHERZER, a citizen of the United States of America, and resident of Ypsilanti, county of Washtenaw, State of illichigan, have invented certain new and useful Improvements in and Relating to Regulating Centrifugal Pumps, of which the following is a specification.

This invention relates to centrifugal pumps; and the object and nature of the invention will be readily understood. by those skilled in the art in the light of the following explanation of what l now belieVe to be the preferred method of practicing my invention, and of the following description of What I believe to be the preferred mechanical expression or embodiment of the invention from among other forms, constructions and arrangements within the spirit and scope thereof.

Centrifugal pumps are each designed and rated for a certain capacity. at a certain speed, meaning that the particular pump is most eliicient at that capacity and speed. It often happens that there is call or demand for a centrifugal pump of a capacity somewhat different from that of standard sizes or constructions. For instance, there may be call for a pump of slightly less ca pacity than the standard size most closely approaching the desired capacity, and of much greater capacity than will be efficiently taken care of by the next smaller standard size. In such instances, it is the common practice to fill the order with the larger size pump fitted with a motor large enough to drive the pump at its maximum capacity for that speed. Economical loss results as both the pump and motor are forced to operate at less than their best ciliciency, as is well understood by those skilled in the art, without further explanation.

It is possible in a centrifugal pump to develop suflicient force by high velocities of rotation to throw large quantities of water out of the discharge of the runner, said quantity increasing With the peripheral speed of the runner, nevertheless atmospheric pressure is alone responsible for lifting the water up to the level of thepump and into the runner, and since the atmospheric pressure is more or less fixed in amount at any given locality, no more water can be discharged from the runner than the atmospheric pressure is capable ofde- Serial No. 487,052.

livering to the suction side of the runner.

hen the speed of the runner is such as to cause the discharge to exceed the capacity of the suction inlet, the pressure falls rapidly with an increase in discharge and the pump is said to break off. It will hence be noted that broadly spealn'ng, the ulti mate limit of the capacity of a given centrifugal pump is fixed by the design of its suction inlet or side.

\Vith the usual construction, centrifugal pumps are so designed that the relation be tween the capacity and pressure for a given speed is definitely fixed by the design of the runner suction inlet or the suction side of the pump. in pumps of the usual construction, this fixed relation cannot be readily changed or altered after the pump is built, and in fact no provision is usually made for altering or varying this fixed relation.

It is an object of my invention to vary the normal capacity of a centrifugal pump at a given speed by varying, within certain bounds, the capacity of the suction side of the pump whether the variation be in the suction inlet of the casing or the suction inlet in the runner itself; and a further object is to provide a centrifugal pump with means on its suction side whereby the capacity of the suction inlet can be varied at the factory preferably'in such manner that such inlet cannot be easily tampered with or varied after the pump has left the factory or after it has been installed. In other words, my invention contemplates the provision of means whereby the capacity of a centrifugal pump may be readily regulated, varled or adjusted, at the factory to suit any conditions of capacity and pressure within the possible range of the pump, by increasing or decreasing the capacity of the uction inlet within certain bounds.

With these and other objects in view, my invention consists in thus controlling the capacity of the pump suction inlet within bounds determined by the possible range of the pump runner, and in certain novel features in construction, arrangement or combination as more fully and particularly set forth and specified hereinafter.

Referring to the accompanying drawings:

Fig. 1 shows a centrifugal pump runner embodying my invention, in section in a plane parallel with the axis of the runner.

iuigsv 2, 8 and 5 are sections showing modified embodiments of my invention.

Fig.4. shows the runner of Fig. l in side elevation looking at the suction side thereof.

In the drawings, 1 show runners oli'the enlosed type, for centrifugal pumps having shells or casings of any suitable construction and formation, and 1 herein employ the term centrifugal to include all pumps of that general type whether single or double suction, single or multi-stage, single or multiple runner. V

In each instance shown in the drawings, the runner comprises a hub 6, opposite side plates 2, 3, connected by vanes a providing the peripheral runner discharge and the center or side runner inlet or suction opening. In. each instance shown, the suction or inlet side of the pump is equipped with means whereby the capacity of the suction inlet can be varied, regulated or adjusted from the minimum capacity fwithin the range of operation oi the particular runner to the maximum or 11011112110311) city within the range of operation of the particular runner. Such means in each instance shown provides the pump with what might be termed a contracted or choked variable or adjustable suction inlet opening 5.

In the particular emhodiment illustrated by Figs. 1 and 4t, the runner is formed with the usual longitudinal cylindrical neck 3 surrounding and defining the normal suction inlet of the runner and forming the usual concentric bearing surface 3 at the suction side of the runner. This runner is designed for most eiiicient operation, at predetermined capacity and'speed, requiring; certain predetermined powcijwhere the suction inlet is of maximu.incapacity to supply liquid to maintain the normal capacity of the runner at that speed. This maximumcapacity suction inlet is usually formed by an unobstructed annular opening between the runner hub or sleeve and the cylindrical inner surface of the neck 3 concentric with the outer surface 8 'otsaid neck. for instance as appears in the runners of Figs. 2 and 5.

Now, in this particular embodiment, 1 contract or choke this normal .or maximum capacity suction inlet of the runner by forming the neck 3 with an annular inwardly extending flange to torm'the runner suction inlet 5 of the minimum, capacity within the range oi operation oi? the pump. The suction inlet without said flange is of maximum capacity within. the range of the pumpf Any desired suction ii'ilet capacity between these extremes, is attained by boring out or otherwise reducing the radial width of the flange 5 to increase the radial width or" the suction inlet 5.

In the embodiment disclosed by Fig. 2,

the same result as in rig. 1, is attained by forming the otherwise usual wearing or pack 111g ring 13, with the annular inwardly e tendlng flange 13 to contract or choke the normal capacity suction inlet oi? the pump to the suction inlet 5 or minimum capacity. This flange can be bored out or otherwise reduced to provide a suction inlet of any desired capacity between minimum and normal or maximum. The normal or maximum suction .inlet capacity is (in Fig. defined by the cylindrical inner surface of the runner neck 3.

Thepacking or wearing ring 13 in effect constitutes a part of the pump casing, which otherwise does not appear in Fig. 2, and no part oi which is shown in llig. 1. The same result as in Figs. 1 and 2, is attained in Fig. 8 by the employment of a regulating sleeve or cylinder secured to rotate with the runner and inserted in and concentric with the run ner neck and formed with a flange l0 abutting the outer end edge oi the runner neck. This cylinder provides two variable or ad justablc sr .ton inlet openings 5, of minimum capacity.

ii the opening 5 is of? maximum capacity, i. e., will supply the pump when operatin at normal or maximum capacity, the contracted or choked openi 7 can be increased in capacity by shortci mg the cylinder through reinova of metal 'l'rom its inner end, or the suction inlet of the runner can be increased to maximum capacity by removal of the cy inder. lit the opening '7 is oi maximum capacity and theopening 5 cl? minimum capacity, the interior ('liameter ot the cylinder can be increased by boring to increase the capacity of inlet 5.

The suction inlet oi this runner oi i ig. 3, can also be decreased to the mininuun, ii need be, by removing metal, at S, 'li'rom either annular wall to permit additional longituiilinal movement of the cylinder into the runner to further reduce the capacity of the suction inlet 7.

In Fig. 5, the suction inlet of the runner su rounded by the cylindrical. inner surface of runner neck 3 is ct maximum or normal capacity, and control'oi' the capacity or the pump suction is attained. through means con.- tractinn' or choking the suction inlet to the pump shell or casing. -For instan 'e, a portion 11 of the suction ot the pump casing; is shown, and a portion 12 of the suction pipe line lGflCllligZ" to the pump casing.

lhe suction entrance to the pump casino; 1]. choked or contracted to prmhu-o the minimum capacity suction inlet 5, by a plate or tliski). This openin; 5 thrc this plat. can be bored out to produce any desire l capacity between. maximum and minimum. In this instance, the maximur capacity is defined by the internal dian'ieters of the suction entrance of the pump casing and the runner inlet.

1 do not wish'to limit my invention to the particular constructions and arrangements disclosed, as the desired result can be tained by various other means and arrangements to permit eiiicient operation of standardizcd sizes of centrifugal pumps, under conditions, capacities and heads for which the standardized or other pumps are not otherwise adapted for efficient operation.

From the foregoing it will be noted that the result sought is accomplished by the provision of what might be termed a variable, adjustable or regulating opening on the suction side of the pump through which the water must pass on its way to the runner.

F or any given opening there is a limited amount of water that the atmospheric pressure can force through it and this will assist in limiting the discharge of the pump. hen more water is desired the opening may be made larger and when less it can be made smaller.

It often happens that a pump is desired to work against a smaller capacity and somewhat higher pressure than would be the best for the given pump at that speed. In such cases, the increase of capacity which usually accompanies a decrease in pressure would be of no value and in cases may be even a serious disadvantage since it usually requires greater power to drive the pump. This increase in power may overload or even burn out the motor driving the pump. The function of my regulator is to limit the capacity and hence the power to any desired amount, within limits, by the use of a variable sized orifice on the suction side of a centrifugal pump. The regulator may be constructed in many different ways and may be placed at any point on the suction side of a centrifugal pump.

In general I might say, that I Wish my invention to cover the ideaof the regulation of the capacity head, power or either in a centrifugal pump by the use of adjustable or semi-adjustable openings on the suction side through which the water must flow.

It is evident that various changes, modifications and variations might be resorted to without departing from the spirit and scope of my invention, and hence I do not wish to limit myself to the exact disclosures hereof.

WVhat I claim is:

l. A centrifugal pump having a suction inlet determining the maximum capacity of the pump at a certain speed, and provided with means reducing said suction inlet to a permanently fixed predetermined capacity between said maximum capacity and the minimum capacity of the pump at that speed.

2. A centrifugal pump having a suction inlet determining the maximum capacity of the pump at a certain speed, and provided with means rotating with the pump runner, reducing said suction inlet to a permanently fixed predetermined capacity between said maximum capacity and the minimum capacity of the pump at that speed.

3. A centrifugal pump of a standard capacity and speed, before installation reduced to a fixed predetermined capacity less than said standard capacity but not below the minimum capacity of the pump at such speed, said pump having a suction inlet for said standard capacity provided with means reducing said inlet to said permanent predetermined fixed capacity.

4:. A centrifugal pump designed for a certain capacity at a certain speed and having a suction inlet of such capacity, said pump having means non-accessible and fixed after installation of the pump and reducing said suction inlet to a fixed and non-variable known capacity not less than the minimum capacity of the pump at that speed.

5. A. centrifugal pump having a suction inlet of known maximum or normal capacity, said pump provided with an annulus which is relatively fixed and inaccessible after pump installation and which reduces said maximum suction inlet to a predetermined capacity that is fixed and non-variable after installation and is within the range of operation of the pump, said annulus being so constructed and arranged that the reduced suction capacity above the minimum can be attained by the removal of material from the annulus before pump in stallation.

6. A centrifugal pump having a suction inlet of known maximum or normal capacity, said pump provided with an annulus which is relatively fixed and inaccessible after pump installation and which reduces said maximum suction inlet to a predetermined capacity that is fixed and non-variable after installation and is within the range of operation of the pump.

7. A centrifugal pump having a suction inlet of known maximum capacity for a certain pump speed, said pump having an annulus that is relatively fixed after pump installation with a bore or opening of predetermined fixed non-variable area reducing said suction inlet capacity, as and for the purposes substantially as described.

8. A centrifugal pump having a suction inlet of known maximum capacity for a certain pump speed, said pump having an annulus as a fixed part of the pump runner with a bore or opening of predetermined fixed non-variable area reducing said suction inlet capacity, as and for the purposes substantially as described.

ALLEN F. SHERZER. 

